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by EliRivers 1256 days ago
In your examples interacting with a circuit, you affect what you're observing because you have physically changed it. You have poked it with a metal stick and you have physically changed the system you are observing.

With QM, it's NOT that you are poking it with a stick. It's NOT that you are physically interacting with the system and physically changing it because you've poked it with a stick (be it literally or metaphorically).

With QM, having knowledge of the system is what changes it. Observing it is what changes it; not some physical change you make to the system because you're poking it with a tool. The fact that it is observed is what changes it.

Having knowledge about the system changes it, no matter how you got that knowledge, even if you got that knowledge in a way that cannot possibly have physically affected the system.
2 comments
zeroonetwothree 1256 days ago
It’s not “knowledge” that changes it—this seems to give some mystical power to human minds. It’s that it interacts with the “outside world”, ie decoherence. Which isn’t very magical in itself.
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EliRivers 1256 days ago
By "knowledge", I include any kind of record. Anything. Something different in the universe. Even if nobody actually looked at it, even if it wasn't actually recorded. Not magical human minds indeed; just that the measurement happened. Information created. However we like to word it. English isn't a great language for this. I suspect no language really suits.

Which isn’t very magical in itself.

Well, it's also supremely magical. That's the whole weirdness of it all.

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zeroonetwothree 1256 days ago
I don’t think decoherence is magical, indeed it’s what happens every day all the time such that we never perceive quantum effects in our everyday lives!
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s0ulphire 1256 days ago
You do realise the definition is "beautiful or delightful in a way that seems removed from everyday life"...seems like you're set on defining "magical" as "related to druids" lol, when nobody is using the term in that way.
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rsp1984 1256 days ago
even if you got that knowledge in a way that cannot possibly have physically affected the system.

How can that be possible? Any examples?

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TheOtherHobbes 1256 days ago
https://en.wikipedia.org/wiki/Elitzur%E2%80%93Vaidman_bomb_t...
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